page_title: Chirality
section_title: Chemistry
hierarchical_section_title: Chirality / Chemistry
caption_attribution_description: English: Zwitterion-Alanine
context_page_description: Chirality is a property of asymmetry important in several branches of science. The word chirality is derived from the Greek χειρ, "hand," a familiar chiral object.
  An object or a system is chiral if it is distinguishable from its mirror image; that is, it cannot be superimposed onto it. Conversely, a mirror image of an achiral object, such as a sphere, cannot be distinguished from the object. A chiral object and its mirror image are called enantiomorphs or, when referring to molecules, enantiomers. A non-chiral object is called achiral and can be superposed on its mirror image.
  The term was first used by Lord Kelvin in 1893 in the second Robert Boyle Lecture at the Oxford University Junior Scientific Club which was published in 1894:
  I call any geometrical figure, or group of points, 'chiral', and say that it has chirality if its image in a plane mirror, ideally realized, cannot be brought to coincide with itself.
  Human hands are perhaps the most universally recognized example of chirality.
context_section_description: A chiral molecule is a type of molecule that has a non-superposable mirror image. The feature that is most often the cause of chirality in molecules is the presence of an asymmetric carbon atom.
  The term "chiral" in general is used to describe the object that is non-superposable on its mirror image.
  In chemistry, chirality usually refers to molecules. Two mirror images of a chiral molecule are called enantiomers or optical isomers. Pairs of enantiomers are often designated as "right-", "left-handed" or, if they have no bias, "achiral". As polarized light passes through a chiral molecule, the plane of polarization, when viewed along the axis toward the source, will be rotated clockwise (to the right) or anticlockwise (to the left). A right handed rotation is dextrorotary (d); that to the left is levorotary (l). The d- and l-isomers are the same compound but are called enantiomers. An equimolar mixture of the two optical isomers will produce no net rotation of polarized light as it passes through. Left handed molecules have l- prefixed to their names; d- is prefixed to right handed molecules.
  Molecular chirality is of interest because of its application to stereochemistry in inorganic chemistry, organic chemistry, physical chemistry, biochemistry, and supramolecular chemistry.
  More recent developments in chiral chemistry include the development of chiral inorganic nanoparticles that may have the similar tetrahedral geometry as chiral centers associated with sp3 carbon atoms traditionally associated with chiral compounds, but at larger scale.   Helical and other symmetries of chiral nanomaterials were also obtained.
caption: (S)-Alanine (left) and (R)-alanine (right) in zwitterionic form at neutral pH
exif: {}